When transmitting amplitude and/or phase modulated signals, it is known to provide the receiver with a gain or level regulating device, which equalizes or smoothes any fluctuation in the level of the signal occurring during transmission. For this purpose, a capacitor is charged to respective peak values of the signal, an increasing voltage across the capacitor being utilized to decrease the amplification of a pre-amplifier, and therefore to decrease the level of the signal, while a decreasing potential across the capacitor is utilized to increase the amplification of the pre-amplifier, and thus to increase the level of the signal.
To prevent changing the amplification of the signal continuously in the pre-amplifier, the gain control only takes effect, once a predetermined threshold potential across the capacitor has been exceeded.
In the transmission of images of a carrier modulated by amplitude and phase modulation, overshoots may, however, occur in the transmitted signal during phase changes, which in turn lead to a drastic reduction of the amplification, for example, of the pre-amplifier. This in turn leads to an undesirable decrease of the level of the signal, particularly if such phase changes or phase jumps occur frequently.